Add JRuby 9.1.17.0

The jruby-launcher needs to be tested at least one major JRuby version back. In addition, there are users out there running JRuby 9.1.x that may be unable to upgrade at present.

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
       matrix:
         os: [ ubuntu-16.04, ubuntu-18.04, macos-latest, windows-latest ]
         # Use various version syntaxes here for testing
-        ruby: [ 2.2, 2.3, .ruby-version, .tool-versions, ruby-head, jruby, jruby-head, truffleruby, truffleruby-head ]
+        ruby: [ 2.2, 2.3, .ruby-version, .tool-versions, ruby-head, jruby-9.1, jruby, jruby-head, truffleruby, truffleruby-head ]
         exclude:
         - os: windows-latest
           ruby: truffleruby
@@ -125,3 +125,6 @@ jobs:
     - uses: actions/checkout@v2
     - run: yarn install
     - run: yarn run lint
+    - run: yarn run package
+    - name: Check generated files are up to date
+      run: git diff --exit-code

CONTRIBUTING.md

@@ -0,0 +1,21 @@
+# Contributing
+
+## Installing dependencies
+
+```bash
+$ yarn install
+```
+
+`npm` doesn't install the correct dependencies for `eslint` so we use `yarn`.
+
+## Regenerating dist/index.js
+
+```bash
+$ yarn run package
+```
+
+It is recommended to add this as a `git` `pre-commit` hook:
+
+```bash
+$ cp pre-commit .git/hooks/pre-commit
+```

README.md

@@ -18,7 +18,7 @@ This action currently supports these versions of MRI, JRuby and TruffleRuby:
 | Interpreter | Versions |
 | ----------- | -------- |
 | Ruby | 2.2, 2.3.0 - 2.3.8, 2.4.0 - 2.4.9, 2.5.0 - 2.5.7, 2.6.0 - 2.6.5, 2.7.0, head, mingw, mswin |
-| JRuby | 9.2.9.0 - 9.2.11.0, head |
+| JRuby | 9.1.17.0, 9.2.9.0 - 9.2.11.0, head |
 | TruffleRuby | 19.3.0 - 20.0.0, head |
 | Rubinius | 4.14 |
 

pre-commit

@@ -0,0 +1,4 @@
+#!/usr/bin/sh
+set -e
+yarn run package
+exec git add dist/index.js

ruby-builder-versions.js

@@ -10,6 +10,7 @@ export function getVersions(platform) {
       "head"
     ],
     "jruby": [
+      "9.1.17.0",
       "9.2.9.0", "9.2.10.0", "9.2.11.0",
       "head"
     ],